Solution feed for a cleaning machine



Feb. 12, 1957 c. L. PRITCHARD SOLUTION FEED FOR A CLEANING MACHINE FiledJune 14,- 1954 I N V E NTO R Clarence LPr/fchara' United States Patent2,781,230 SOLUTION FEED FOR A CLEANING MACHINE Clarence L. Pritchard,San Leandro, Califi, assignor to Malsbary Manufacturing Company,Oakland, Calif., a

The present invention relates to improvements in a solution feed for acleaning machine of the character described in the Malsbary Patent No.2,295,228, although the principle of the invention may be applied toother purposes.

The cleaning machine is intended generally for cleaning motor vehiclesor heavy industrial machinery by means of a strong spray of hot water orsteam having a cleaning solution embodied therein.

The machine comprises in its general features, a coil having means forheating the same, means for forcing water with an admixture of acleaning solution through the coil, a hose connected to the dischargeend of the coil and a discharge nozzle with a relatively small orificeat the free end of the hose.

In the patent, it is proposed to use a pump for forcing the waterthrough'the coil, and the solution is fed to the pump from a suitabletank in a separate path and is mixed with the water in the pump.

It is advisable, however, in the interest of economy, and whereconditions warrant, to connect the coil directly to a city Water supply,and in that case the feeding of the solution into the water becomes aproblem which is the object of the present invention to solve.

In this connection it should be noted that the solution shouldpreferably be fed into the water before it reaches the coil, because thesolution has a beneficial effect in maintaining the coil in a cleancondition. Since the present invention is directed principally to thesolution feed, the parts of the cleaning machine not involved in theunderstanding of the invention have been omitted from the drawing, forthe sake of simplicity.

Further objects and advantages of my invention will appear as thespecification proceeds, and the new and useful features of my solutionfeed will be fully defined in the claims attached hereto.

The preferred form of my invention is illustrated in the accompanyingdrawing, forming part of this application, in which:

Figure 1 shows, in side elevation, the general layout of the invention;

Figure 2, a top plan view of my solution tank; and 1 Figure 3, a partsectional, part side view of the tank, the section being taken alongline 3-3 of Figure 2.

While I have shown only the preferred form of the invention, I wish tohave it understood that various changes or modifications may be madewithin the scope of the claims attached hereto, without departing fromthe spirit of the invention.

Referring to the drawing in detail, the solution tank 1 may be of anysuitable form, and is preferably made cylindrical, and dimensioned tohold approximately one gallon of. the solution. It may be secured to themachine in any suitable manner, and is here shown as being secured uponthe side of the coil housing 2 by means of suitable brackets 3.

It should be noted that the location of the tank with respect to themain conduit makes little diiference, since gravity feed forms no partof the invention.

The solution in the tank may be of any suitable mixture of water andcleaning compound, and may be assumed, for the purposes of the presentinvention, to have approximately the same specific gravity as the waterfed through the machine.

In the general operation of the machine, it is intended that thesolution be fed into the main flow of Water in a mere trickle, so thatone gallon of solution will serve many gallons of water passing throughthe machine.

The cleaning machine, itself, is represented in the drawing by theconduit 4, which at one end, indicated at 5, is connected to a suitablesource of water under considerable pressure, such as a city watersupply, and at the other end, indicated at 6, to the heating coil of thecleaning machine. The latter again connects, through a suitable lengthof hose, with a discharge nozzle, so that the water passes through thecoil under pressure and is discharged through the nozzle, either in theform of hot water or of steam, or of a mixture of both steam and water,depending upon results desired.

In the operation of the machine, it is desired that the water be fed ata constant volume, regardless of changes in pressure in the city watersupply.

For the purposes of the present invention, I introduce a slightresistance in the conduit, which may take the form of a flap valve 7pivoted in the conduit, as at 8, and having a light spring 9 bearingagainst the same and tending to close it. This valve creates a slightpressure differential which is utilized to by-pass a small amount ofwater from the main flow into the outlet pipe 10 which leads to the topof the tank and connects thereto through the aperture 11 in a cap 12fitted into the upper end of the tank.

Immediately underneath the cap 12, and secured to the bottom thereof bymeans of a screw 13, is a bafiie 14 in the form of a disc which has adiameter slightly smaller than the inner diameter of the tank, so thatthe water entering through the pipe 10 first gently joins the liquidpresent in the space above the bafiie, and then causes the latter togently feed around the periphery of the disc to join the liquid belowthe baffle.

The pipe 10 is provided with a metering valve 15 which may be set tometer out the water drop-wise, in a thin trickle, and I have found thatWater thus entering the tank tends to remain on top of the solution inthe tank, and does not mix with the latter.

The water merely forms a surface layer, which increases in size as theprocess is continued and develops into a piston which drives thesolution through the aperture 16 in the bottom of the tank at the samerate that the water enters through the top.

The bottom aperture 16 connects through the return pipe 17 with theconduit 4 downstream of the resistance 7. Due to the fact that the waterand the solution do not mix in the tank, all of the solution thusdischarged into the conduit will be of uniform strength, and the tankwill keep feeding solution of original strength until the solution iscompletely exhausted, and the whole tank is filled with water, at whichtime it becomes necessary to refill the tank with solution.

The connection 18 between the aperture 16 and the return pipe 17 isequipped with a shut-off valve operable by a handle 19 for disconnectingthe tank from the return pipe in case a refill becomes necessary.

The bottom of the tank also has a quick-opening valve 20, which may beremoved upon turning the handle through one-quarter of a turn, foreffecting a quick draining of the water from the tank.

The top of the tank has a similar quick-opening valve 21 which is shownin detail as comprising a cylindrical a -3 valve-head Z'Z-fitting in anopening '28 in the cap and formed with a pair of tongues 24 adapted foranchoring underneath a pair of lugs 25 when the valve is turned By meansbf haadl-esshownat 26; The valve be pulled out eateries of a turnoffthfe Ban-ales iii-the appease d-irectioh, and the spelt-mg 23h ureaused for re fillin'g th'e tank. a

The cdridui't I is cbhnected t6 the top bf the tank through a T-fitting27 which is provided with breeder hole controllable through a handle -28for v'e'iitirig' sue pisses. This venting becomes necessary, after thetank has been filled with solution to its limit and the valve 22*hasbeenrte-applied,- in order "to allow water f ibm the pips 10 to completelyfill pockf's'forfiled in the can fietidhs asavetfi soIut-io'h level; V

It'w'fill be noted that the-portion brine bafiie oidisc 14 'dispb'sedunderneath the filler hole i'sbent dbwhward; as at 1'4; This is tea thepurpose 0? giving some aadi efial else-lance for the solhtiofi-dhringthe filling operation; 1

In use, assuming that the tank has been properly filled with solutionand that water is forced through the condfi-it 4 under high pressure,the resistance 7 will create a pressure differential which causes asmall portion of the water to be lay-passed to the top of the taiik, theextra amount depending upon the setting of the metering valve '15, whichis set to deliver a mere dribble of water to the tank. Y i The feedingof water is very gentle,- and the battle aids to efit such a smooth andgradual transfer of the water that the latter does not mix with thesolution; but only forms agradually increasing layer of water above thesolution with the result that the solution is crowded tliiftigh theconduit 17 into the conduit downstream of the resistance.

Thus, the solution is red into the flow of water at a rate.corresponding to the openingof the metering valve, and since thesolution is not mixed with any water,- a solution of uniform strengthwill be fed into the conduit until the tank is emptied completely.

When all the solution has been fed; the tank is filledwater, and it isnecessary: to re-fill the tankwith solution. This operation, the tank isfirst disconnected from the system by closing the valve 19. i

' Next the bottom valve 20 is removed to allow the water to drain out.This valve is then replaced, and the top valve- 21 is removed to openthe filler hole,- whereupon the tank is filled with solutionto itscapacity.

Next the va'lve' 21 is replaced, whereupon the metervalve I is operatedto' allow the liquid from' the conduit to fill any existing voids, thevent 28 allowingtrappe'd air to" escape.

'Upoh reopening the valve 19 inthe bottom of the tank and proper settingof the metering valve; the tank is n'ov'd ready for further dispensingoperations;

While the solution has been described as having ap proximately the samespecific gravity as the water, it should be understood that its gravityis slightly higher than that of the water, the chemicals adding aboutone pound per gallon to the specific gravity.

1 claim:

1. In combination, a conduit having means for passing a liquidtherethrough uhder pressure, a resistance in said conduit adapted toslightly impede the flow of the liquid therethrough, a bypass for theconduit including an outlet passage disposed upstream of the resistance,a return passage disposed downstream of the resistance anda tankconnecting the; two passages, the tank having a -second liquid thereinof approximately the same spe cific gravity the fi' i quid; the "outletpassage having unrestricted conn'ec tank, and the return passage beingconnected 1 whereby the first liquid is made to cause-the, second liquidto feed into the conduit the outlet and return passages being ceiiiictdfo' thecondtiit closely adjacent the resistance so as to render theinherent pressure drop in the conduit between the passages substantiallynegligible, n t ars n b n iau dz qm lled a l v ab estate n -y ,it jss iitq mammifimep esur differential i lt' h p sag s, ti e to t ire mfi esan ai s etime; sse fi d we sures, and-being sufficiently slight tocause liquid t ass through the by-pass in a gentle flow, and a Iii eringvalve in" the outlet passag and operable to reduce the w wuafith gbx-r'w v o.

on'duit having means for'pass git underpressure, a resist'ance t: flvlihe b f passfor the conduitincluding g St ps re m ffih ta c ae mvia d o edownstr mx fthe x ist and a'tank connecting the twcipass'agels; the tankhaving 1 a se nd li ui t e n o ,ait fo i l i h S me 5P fi g at y he firsliq th l ass e. Ha in fi ir t' t d' wm Wi lie e of thet n a d e returnpassage being eon'nected to the bottom thereo'fi whereby the firstliquid is'made to cause the second liqeid m fed into the conduit, the"outlet and r'emrn passtg'es bfeing connected to the conduit closelyadjacent tl' lsi i sasid a qr ild t e mc t r s e p in thefconduitbetween" the pas-sage substantially negligible, and resistance beingliquid-controlled' and variable in response to liquid pressure tomaintain" the I pressure difierential betw en the two passages" due tothe resist-'- ance substantially constant for different liquidpressures, and being suff ciently slight to cause Iiquidto pass throughthe bY-fpass'in a gentle flow, and a metering valve in the outletpassage and operable to reduce the fiow'through' the bypalssfto1 a"trickle", the tank having a; baffle under neatfr the outlet passagedischarge toreduce disturbance of th'f liquid in th e tank due to thefeed from the outlet passage to a minimum;

References Cited in the fi Ie" of this patent

